统一编码处理

Web应用全链路统一编码，避免各环节编码不一致导致乱码。

全链路编码配置

浏览器 → 服务器 → 数据库 → 响应 → 浏览器
  ↓        ↓         ↓        ↓        ↓
 UTF-8   UTF-8    UTF-8    UTF-8   UTF-8

请求编码

POST请求

<!-- web.xml配置编码过滤器 -->
<filter>
    <filter-name>characterEncodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
    <init-param>
        <param-name>encoding</param-name>
        <param-value>UTF-8</param-value>
    </init-param>
    <init-param>
        <param-name>forceEncoding</param-name>
        <param-value>true</param-value>
    </init-param>
</filter>
<filter-mapping>
    <filter-name>characterEncodingFilter</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

GET请求

<!-- Tomcat server.xml -->
<Connector port="8080" protocol="HTTP/1.1"
           URIEncoding="UTF-8"
           connectionTimeout="20000" />

响应编码

SpringMVC配置

@Configuration
@EnableWebMvc
public class WebConfig implements WebMvcConfigurer {

    @Override
    public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
        configurer.defaultContentType(MediaType.APPLICATION_JSON_UTF8);
    }
}

JSP页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>

HTML页面

<meta charset="UTF-8">

数据库编码

MySQL配置

-- 创建数据库
CREATE DATABASE db_name CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;

-- 创建表
CREATE TABLE user (
    id INT,
    name VARCHAR(100) CHARACTER SET utf8mb4
) CHARACTER SET utf8mb4;

JDBC连接

jdbc.url=jdbc:mysql://localhost:3306/db?useUnicode=true&characterEncoding=utf8mb4&serverTimezone=Asia/Shanghai

文件编码

IDEA设置

• File Encoding：UTF-8
• Project Encoding：UTF-8
• Properties Files：UTF-8

Maven配置

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>

JSON编码

Controller返回JSON

@RestController
public class ApiController {

    @GetMapping(value = "/data", produces = "application/json;charset=UTF-8")
    public Map<String, Object> getData() {
        Map<String, Object> result = new HashMap<>();
        result.put("name", "张三");
        return result;
    }
}

编码检查清单

全链路统一UTF-8编码，是解决乱码的根本方案。

要点总结

• Tomcat URIEncoding：解决GET请求乱码
• CharacterEncodingFilter：解决POST请求乱码
• contentType charset：解决响应乱码
• JDBC characterEncoding：解决数据库乱码
• IDE和项目编码：解决源码乱码